A suspected truck bomb has ripped through the heart of Kabul's diplomatic district, killing at least 90 people and wounding hundreds, in a powerful blast described by officials as "one of the biggest" to have hit the Afghan capital.

Afghanistan has suffered large attacks almost monthly since the beginning of 2017.

Civilian casualties in Afghanistan in 2016 were the highest recorded by the United Nations, with nearly 11,500 non-combatants - one-third of them children - among the victims.